nptl: Add C11 threads cnd_* functions

This patch adds the cnd_* definitions from C11 threads (ISO/IEC 9899:2011),
more specifically cnd_broadcast, cnd_destroy, cnd_init, cnd_signal,
cnd_timedwait, cnd_wait, and required types.

Mostly of the definitions are composed based on POSIX conterparts, and
cnd_t is also based on internal pthreads fields, but with distinct internal
layout to avoid possible issues with code interchange (such as trying to pass
POSIX structure on C11 functions and to avoid inclusion of pthread.h).  The
idea is to make it possible to share POSIX internal implementation for mostly
of the code making adjust where only required.

Checked with a build for all major ABI (aarch64-linux-gnu, alpha-linux-gnu,
arm-linux-gnueabi, i386-linux-gnu, ia64-linux-gnu, m68k-linux-gnu,
microblaze-linux-gnu [1], mips{64}-linux-gnu, nios2-linux-gnu,
powerpc{64le}-linux-gnu, s390{x}-linux-gnu, sparc{64}-linux-gnu,
and x86_64-linux-gnu).

Also ran a full check on aarch64-linux-gnu, x86_64-linux-gnu, i686-linux-gnu,
arm-linux-gnueabhf, and powerpc64le-linux-gnu.

	[BZ #14092]
	* conform/data/threads.h-data (cnd_t): New type.
	(cnd_init): New function.
	(cnd_signal): Likewise.
	(cnd_broadcast): Likewise.
	(cnd_wait): Likewise.
	(cnd_timedwait): Likewise.
	(cnd_destroy): Likewise.
	* nptl/Makefile (libpthread-routines): Add cnd_broadcast,
	cnd_destroy, cnd_init, cnd_signal, cnd_timedwait, and cnd_wait
	object.
	* nptl/Versions (libpthread) [GLIBC_2.28]: Likewise.
	* nptl/cnd_broadcast.c: New file.
	* nptl/cnd_destroy.c: Likewise.
	* nptl/cnd_init.c: Likewise.
	* nptl/cnd_signal.c: Likewise.
	* nptl/cnd_timedwait.c: Likewise.
	* nptl/cnd_wait.c: Likewise.
	* sysdeps/nptl/threads.h (cnd_t): New type.
	(cnd_init): New prototype.
	(cnd_signa): Likewise.
	(cnd_broadcast): Likewise.
	(cnd_wait): Likewise.
	(cnd_timedwait): Likewise.
	(cnd_destroy): Likewise.

1 files changed, 34 insertions, 0 deletions

diff --git a/nptl/threads.h b/nptl/threads.h
index 32f7cf8f75..e46b1b7f32 100644
--- a/nptl/threads.h
+++ b/nptl/threads.h
@@ -60,6 +60,12 @@ typedef union
   long int __align __LOCK_ALIGNMENT;
 } mtx_t;
 
+typedef union
+{
+  char __size[__SIZEOF_PTHREAD_COND_T];
+  __extension__ long long int __align __LOCK_ALIGNMENT;
+} cnd_t;
+
 /* Threads functions.  */
 
 /* Create a new thread executing the function __FUNC.  Arguments for __FUNC
@@ -140,6 +146,34 @@ extern void mtx_destroy (mtx_t *__mutex);
    All calls must be made with the same __FLAGS object.  */
 extern void call_once (once_flag *__flag, void (*__func)(void));
 
+
+/* Condition variable functions.  */
+
+/* Initialize new condition variable pointed by __COND.  */
+extern int cnd_init (cnd_t *__cond);
+
+/* Unblock one thread that currently waits on condition variable pointed
+   by __COND.  */
+extern int cnd_signal (cnd_t *__cond);
+
+/* Unblock all threads currently waiting on condition variable pointed by
+   __COND.  */
+extern int cnd_broadcast (cnd_t *__cond);
+
+/* Block current thread on the condition variable pointed by __COND.  */
+extern int cnd_wait (cnd_t *__cond, mtx_t *__mutex);
+
+/* Block current thread on the condition variable until condition variable
+   pointed by __COND is signaled or time pointed by __TIME_POINT is
+   reached.  */
+extern int cnd_timedwait (cnd_t *__restrict __cond,
+			  mtx_t *__restrict __mutex,
+			  const struct timespec *__restrict __time_point);
+
+/* Destroy condition variable pointed by __cond and free all of its
+   resources.  */
+extern void cnd_destroy (cnd_t *__COND);
+
 __END_DECLS
 
 #endif /* _THREADS_H */